Trends in stroke mortality and its determinants in Finland, 1978--1995

This ecologic study evaluated the role of changes in prevalences of hypertension, antihypertensive drug treatment, smoking, physical activity, obesity, dietary factors, and education profile in stroke mortality declines in Finland. The study tested a treatment hypothesis that there was an association between trends in antihypertensive drug use and stroke mortality in Finland 1978--1995, controlling for hypertension prevalence in 1978--1980 (baseline) and trends in other risk factors.;For 36 age-sex-region specific subgroups of the population aged 35--64 years, average 3-year percent changes (trends) in total, hemorrhagic, and nonhemorrhagic stroke mortality were estimated by Poisson regression using data from the Causes-of-Death Register. The National Public Health Institute health behavior surveys provided data on antihypertensive drug use and other risk factors. Average 3-year changes in prevalences (trends) of risk factors and their associations with stroke mortality trends were estimated by linear regression. Also a lagged observation period of stroke mortality was used, defined as the period 1981--1995. Trends in nonhemorrhagic stroke mortality were not examined in women due to small numbers of deaths.;Favorable trends in risk factors did not explain the variation in stroke mortality trends. The prevalence of antihypertensive drug use declined in most subgroups. Adjusting for demographic variables, baseline hypertension prevalence, and trends in other risk factors, an inverse association favoring the treatment hypothesis occurred between trends in antihypertensive drug use and total and hemorrhagic stroke mortality in the lagged observation period. Trends in education profile were consistently inversely associated with total and hemorrhagic stroke mortality trends in both observation periods. In men, declines in smoking prevalence were associated with declines in total, hemorrhagic and nonhemorrhagic stroke mortality in the lagged period. Increases in the prevalence of physical activity and decreases in that of use of dairy fat were associated with declines in nonhemorrhagic stroke mortality in both periods.;This study provided little support for the treatment hypothesis. Future research should address the associations between trends in stroke mortality, incidence and case-fatality with those in primary and secondary prevention of stroke as well as former and concurrent socioeconomic conditions to better understand the continuing decline in stroke mortality in Finland.